After resuming a session that had disconnected a while ago it errored out as soon as it wanted to start downloading again. My guess is that it didn't wait for my HDD to spin up first since I could hear it spin up just after the error popped up (and it downloaded fine after continuing it just a few minutes later).
A follow up error is that it will not be able to continue the aborted download because it still "locks" the file in its process and can for some reason not override its own lock on it (thus not being able to modify/delete it until WinSCP is completely closed or a tool like Unlocker
Copying files from remote side failed.
Invalid access to memory.